Modular prosthetic foot

ABSTRACT

A modular prosthetic foot characterized by an ankle component; a forefoot component having a circular part with a rounded top surface and at least one flat side surface, said circular part being connected to a rear part of the forefoot component; a forefoot cushion bumper positioned around the circular part; and a heel component.

This is a U.S. national stage application of PCT internationalapplication PCT/US2006/062472 filed on 21 Dec. 2006 and claims priorityof U.S. provisional application Ser. No. 60/756,623 filed on 22 Dec.2005.

I. FIELD OF THE INVENTION

This invention relates to a modular prosthetic foot. The modularprosthetic foot may be utilized worldwide in a variety of climates orterrains. The simple and durable design of the modular prosthetic footmakes it useful for almost any lower extremity amputee.

II. BACKGROUND OF THE INVENTION

Prosthetic ankles and feet are known. For example, U.S. Pat. No.5,030,239 discloses a biomechanical ankle which imitates the threeprimary categories of movement in a human foot. Parallel sole and limbsupporting plates are held in spaced relationship by an upright post.The limb supporting plate is connected to the post with a ball andsocket joint. A helical spring is fixed between the plates to provideresilient support to the anterior portion of the foot in imitation ofnormal muscular control. The ball and socket joint, in cooperation withthe spring, permits the biomechanical ankle to imitate theinversion-eversion, plantar flexion-dorsiflexion, and lateral rotationfound in a normal human foot.

U.S. Pat. No. 7,108,723 B2 discloses a prosthesis for improving the gaitand comfort qualities of the amputee that participates in walking,running and jumping activities. A foot and an ankle of the prosthesisare monolithically formed as a resilient member including a strut whichforms an ankle joint. A hole extends through the resilient member withthe periphery of the hole forming an anterior side surface of the strut.The resilient member anterior to the hole includes a gap to permitmotion about the ankle joint axis while providing a stop indorsiflexion. The hole is elongated upwardly such that the strut isupstanding and anterior convexly curved.

However, there remains a need for a modular prosthetic foot, inparticular, a modular prosthetic foot that mimics the subtalar joint ofa human foot.

III. SUMMARY OF THE INVENTION

In an aspect of the invention, a modular prosthetic foot is providedcharacterized by an ankle component; a forefoot component having acircular part with a rounded top surface and at least one flat sidesurface, said circular part being connected to a rear part of theforefoot component; a forefoot cushion bumper positioned around thecircular part; and a heel component.

In another aspect of the invention, a front part of the ankle componentis about 5° to about 20° higher than a rear part of the ankle component.

In another aspect of the invention, the ankle component furthercomprises an orifice for connection to part of a prosthesis or to apylon.

In another aspect of the invention, the prosthetic foot is provided witha microprocessor device.

Given the following enabling description of the drawings, the apparatusshould become evident to a person of ordinary skill in the art.

IV. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view of a human foot showing the subtalarjoint.

FIG. 2 is a side view of a modular prosthetic foot according to anembodiment of the invention connected to pylon.

FIG. 3 is a perspective view of the modular prosthetic foot according toan embodiment of the invention.

FIG. 4 is a side view of the modular prosthetic foot according to anembodiment of the invention.

FIG. 5 is a front view of the forefoot component of the modularprosthetic foot according to an embodiment of the invention.

FIG. 6A is a top view of the forefoot component of the modularprosthetic foot according to an embodiment of the invention.

FIG. 6B is a side view of the ankle component and heel component of themodular prosthetic foot according to an embodiment of the invention.

FIG. 6C is a bottom view of the ankle component of the modularprosthetic foot according to an embodiment of the invention.

FIG. 6D is a top view of the forefoot cushion bumper of the modularprosthetic foot according to an embodiment of the invention.

FIG. 7 is a bottom view of the modular prosthetic foot according to anembodiment of the invention.

FIG. 8 is a top view of the modular prosthetic foot according to anembodiment of the invention.

FIG. 9 is a front view of the modular prosthetic foot according to anembodiment of the invention.

FIG. 10 is a rear view of the modular prosthetic foot according to anembodiment of the invention.

FIG. 11 is a block diagram of a microprocessor and forefoot cushionbumper according to an embodiment of the invention.

V. DETAILED DESCRIPTION OF THE DRAWINGS

FIGS. 1-11 illustrate a modular prosthetic foot according to theinvention. The invention is an anatomically-based modular prostheticfoot. The prosthetic foot was designed based on the kinesiology of theanatomical foot. In particular, the structure of the prosthetic foot isfocused on mimicking the subtalar joint 100, as shown in FIG. 1.Anatomically, if the tibia internally rotates the subtalar joint everts(pronates). Conversely, if the tibia is externally rotated, the subtalarjoint inverts (supinates). Thus, in theory, the subtalar joint functionsas an elliptical hinge.

In this detailed description, references to “one embodiment”, “anembodiment”, or “in embodiments” mean that the feature being referred tois included in at least one embodiment of the invention. Moreover,separate references to “one embodiment”, “an embodiment”, or “inembodiments” do not necessarily refer to the same embodiment; however,neither are such embodiments mutually exclusive, unless so stated, andexcept as will be readily apparent to those skilled in the art. Thus,the invention can include any variety of combinations and/orintegrations of the embodiments described herein.

The prosthetic foot of the invention is modular, thereby accommodatingvariability in individual subjects and the required functions. As shownin FIG. 2, prosthetic foot 200 comprises three basic components: (1) amiddle section, referred to as an ankle component 205; (2) a toesection, referred to as the forefoot component 210; and (3) a heelsection, referred to as the heel component 215. The forefoot component210 has a front part 210 a and a rear part 210 b. The heel component 215has a front part 215 a and a rear part 215 b.

A. Ankle Component

The ankle component is a unitary body of any effective shape and sizeallowing connection to both the heel component and the forefootcomponent.

The ankle component 205 may be connected to part of a prosthesis or to apylon 220, as shown in FIG. 2. Accordingly, the ankle componentcomprises a receptacle or orifice 305 for connection to the part of aprosthesis or pylon, as shown in FIGS. 3-4 and 8. Connection to part ofa prosthesis or connection to a pylon are the two most common methods ofattachment for endoskeletal or exoskeletal prosthetic systems usedthrough the world. In embodiments, the receptacle or orifice 305 may bepresent on a surface of the ankle component 205 which is opposite asurface to which the forefoot component 210 and the heel component 215are connected or mounted. The ankle component may be connected to theprosthesis part or to the pylon by at least one connector. The connectormay be, but is not limited to, a pin, screw, bolt, shaft, an adheringcompound, or any combination thereof.

B. Forefoot Component

The forefoot component may be of any effective shape and size. Inembodiments, the forefoot component may have an elliptical shape, aJ-shape, a C-shape, or an S-shape.

As shown in FIGS. 2 and 9, the rear part 210 b of the forefoot component210 is connected to the ankle component 205.

As shown in FIGS. 5 and 6A, the rear part of the forefoot component 210b comprises a circular part 510 having a rounded top surface 511 orconvex top surface and at least one flat side surface. The circular part510 preferably has two flat side surfaces 512 a, 512 b (i.e., a flatfront surface and a flat back surface). In embodiments, the circularpart 510 may have a hole 515 extending through its side surfaces, asshown in FIGS. 5 and 6A.

The circular part 510 fits into a slot or hole 610 located on a frontpart of the ankle component 205, as shown in FIGS. 6B-6C. A rod 615 inthe ankle component 205 (as shown in FIG. 6C) may fit through the hole515. Thus, the circular part 510 may rotate around the rod 615 in theankle component. Alternatively, the circular part may have anindentation in its top surface, and the rod in the ankle component mayfit or rest in the indentation.

As shown in FIG. 4, a front part 410 of the ankle component 205 is about5° to about 25°, preferably about 10° to about 15°, higher than a rearpart 415 of the ankle component to mimic the natural foot angle of thesubtalar joint. Accordingly, the circular part 510 is set at an anglewithin the ankle component. The circular part is not perpendicular to anhorizontal axis which is parallel to a level ground surface.

The structure of the circular part 510 and its angle within the anklecomponent allow it to pivot, simulating the subtalar joint of thenatural foot (i.e., an elliptical hinge). Thus, the circular part everts(pronates) and inverts (supinates). In addition, the at least one flatsurface of the circular part keeps the prosthetic foot from rotating toofar forwards and/or too far backwards.

In embodiments, the circular part may be connected or mounted to theforefoot component by at least one connector 705, as shown in FIG. 7. Inembodiments, the connector may be, but is not limited to, a pin, screw,bolt, shaft, an adhering compound, or any combination thereof.

C. Forefoot Cushion Bumper

The motion (eversion and inversion) of the modular foot may be limitedor controlled by a forefoot cushion bumper 310 positioned around thecircular part, as shown in FIGS. 3-4. The forefoot cushion bumper 310may be any effective shape and size. In embodiments, the forefootcushion bumper may have a U-shape or a horseshoe-shape (FIG. 6D),thereby allowing it to clip around or be press fit around the circularpart 510 on the rear part 210 b of the forefoot component 210.

The forefoot cushion bumper controls the range of motion of theprosthetic foot and allows for compression. In embodiments, the forefootcushion bumper may be made comprise a urethane, a dense foam, or anelectro-responsive material, such as an electrically activated polymeror a piezoelectric material.

D. Heel Component

The heel component may be of any effective shape and size. Inembodiments, the heel component may have an elliptical shape, a J-shape,a C-shape, or an S-shape.

As shown in FIG. 2 and FIG. 10, a front part 215 a of the rear componentis connected to the ankle component 205. In embodiments, the heelcomponent 215 may be mounted to the ankle component 205 by at least oneconnector 620, as shown in FIG. 6B. In embodiments, the connector maybe, but is not limited to, a pin, screw, bolt, shaft, an adheringcompound, or any combination thereof. The heel component may beconnected to the bottom of the ankle component or to a side of the anklecomponent.

E. Microprocessor

In embodiments, the modular prosthetic foot of the invention may containa microprocessor. The microprocessor may be located in any component ofthe prosthetic foot, but is preferably located in the forefoot componentor forefoot cushion bumper. The at least one microprocessor device mayallow for monitoring of how the person using the modular prosthetic footwalks.

As shown in FIG. 11, a microprocessor 805 is connected to the forefootcushion bumper 310 and to a power supply 810. Accordingly, themicroprocessor 805 may monitor the forces in forefoot cushion bumper310. In embodiments, the microprocessor may be programmed to change thedensity of an electro-responsive material of the forefoot cushionbumper, thereby allowing greater adaptation to the person's walkingcycle for pliability and enhanced motion.

F. Modularity

The modularity of the prosthetic foot of the invention is advantageous.For example, one forefoot cushion bumper may be substituted with anotherforefoot cushion bumper having one or more different properties (e.g.,different material, different thickness, different density, differentshape) to vary the degree of motion or degree of compression. Inaddition, for a single ankle component, different forefoot componentsand different heel components may be interchanged.

This interchangeability allows for easy variation of the prosthetic footto account for different shoe sizes or foot lengths. Obviously, oneperson may wear a men's shoe size 43 (U.S. shoe size 10), and anotherperson may wear a men's shoe size 39 (U.S. shoe size 7). If the anklecomponent is the same for both people, proper heel components andforefoot components may be readily chosen.

The interchangeability also allows for variation of the prosthetic footbased upon at least one of the individual's height, weight, degree ofphysical activity, or any combination thereof. For example, the heelcomponent and/or forefoot component may be designed to offer more orless compression based on at least one of an individual's activity,weight, height, or a specific gait pattern. In addition, at least one ofthe material, shape, size, density, or method of attachment to the anklecomponent may have an effect on movement and may accordingly be chosenbased upon the specific needs of an individual. The interchangeabilityalso allows for easy replacement of a component that may be found to bedefective or broken.

A health practitioner evaluating an individual, for example a patient,may order at least one of the appropriate heel component or forefootcomponent from a component list which has a scaled matrix to assist inordering the correct component. Bench testing may be used to establishthe scaled matrix. Therefore, the invention can be made adaptable andsuitable depending on many variables.

Any suitable material may be used for the various component parts ofthis prosthetic foot of the invention. In embodiments, the entireprosthetic foot or any one of the ankle component, the forefootcomponent, or the heel component may be manufactured from a carbon fibermaterial. Carbon fiber material achieves the characteristic functions ofenergy return and modularity. As noted, the forefoot cushion bumper maycomprise a urethane, a dense foam, or an electro-responsive material,such as an electrically activated polymer or a piezoelectric material.

The shape of the various component parts is not limited to thatdescribed or illustrated herein. Any shape of a component part may beused so long as the purpose for which the invention is intended. Onehaving ordinary skill in the art would be able to identity suitablematerials and/or shapes of component parts to employ within the scope ofthe present invention.

Although the present invention has been described in terms of particularexemplary and alternative embodiments, it is not limited to thoseembodiments. Alternative embodiments, examples, and modifications whichwould still be encompassed by the invention may be made by those skilledin the art, particularly in light of the foregoing teachings.

1. A modular prosthetic foot, comprising: an ankle component having aslot in a front part of the ankle component; a forefoot componentconnected to a circular part with a rounded top surface, a flat frontsurface, and a flat back surface and at least one flat side surface,said circular part being connected to a rear part of the forefootcomponent and being fit into the slot; a forefoot cushion bumperpositioned around the circular part; and a heel component, wherein theankle component, forefoot component, and heel component are threeseparate components, said forefoot component being directly connected tothe front part of the ankle component and said heel component beingdirectly connected to a rear part of the ankle component, wherein thefront part of the ankle component is about 5° to about 25° higher thanthe rear part of the ankle component with respect to a horizontal axisparallel to a level ground surface so that the circular part is set atan angle within the ankle component.
 2. The modular prosthetic foot ofclaim 1, wherein the front part of the ankle component is about 10° toabout 15° higher than the rear part of the ankle component with respectto a horizontal axis parallel to a level ground surface.
 3. The modularprosthetic foot of claim 1, wherein the circular part has a holeextending from the flat front surface to the flat back surface throughwhich a rod in the slot of the ankle component fits.
 4. The modularprosthetic foot of claim 1, wherein the circular part has an indentationin its top surface in which a rod in the ankle component fits.
 5. Themodular prosthetic foot of claim 1, wherein the heel component isdirectly connected to the ankle component by at least one connectorcomprising a pin, screw, bolt, shaft, adhering compound, or anycombination thereof.
 6. The modular prosthetic foot of claim 1, whereinthe circular part is directly connected to the forefoot component by atleast one connector comprising a pin, screw, bolt, shaft, adheringcompound, or any combination thereof.
 7. The modular prosthetic foot ofclaim 1, wherein the ankle component further comprises an orifice forconnection to part of a prosthesis or to a pylon.
 8. The modularprosthetic foot of claim 1, further comprising a microprocessor device.9. The modular prosthetic foot of claim 1, wherein the forefoot cushionbumper comprises a microprocessor device for monitoring how a personusing the modular prosthetic foot walks.
 10. The modular prosthetic footof claim 9, wherein said forefoot cushion bumper comprises anelectro-responsive material the density of which is changed by themicroprocessor device to adapt to the person's walking cycle.
 11. Themodular prosthetic foot of claim 10, wherein said electro-responsivematerial comprises an electrically activated polymer or a piezoelectricmaterial.
 12. The modular prosthetic foot of claim 1, wherein saidforefoot cushion bumper comprises a urethane material.
 13. The modularprosthetic foot of claim 1, wherein said ankle component, said forefootcomponent, and said heel component comprise a carbon fiber material. 14.A modular prosthetic foot, comprising: an ankle component having a holein a front part of the ankle component; a forefoot component connectedto a circular part with a rounded top surface and two flat sidesurfaces, said circular part being connected to a rear part of theforefoot component and being fit into the hole; a forefoot cushionbumper positioned around the circular part; and a heel component,wherein the ankle component, forefoot component, and heel component arethree separate components, said forefoot component being directlyconnected to the front part of the ankle component and said heelcomponent being directly connected to a rear part of the anklecomponent, wherein the front part of the ankle component is about 5° toabout 25° higher than the rear part of the ankle component with respectto a horizontal axis parallel to a level ground surface, so that thecircular part is set at an angle within the ankle component andsimulates an anatomically-based elliptical hinge.
 15. The modularprosthetic foot of claim 1, wherein the structure of the circular partand its angle within the ankle component allow the circular part topivot, thereby simulating a subtalar joint of a natural foot.
 16. Themodular prosthetic foot of claim 14, wherein the circular part has ahole extending through its side surfaces through which a rod in the holeof the ankle component fits.
 17. The modular prosthetic foot of claim 1,wherein the circular part comprises an elliptical hinge that everts andinverts.
 18. A modular prosthetic foot, comprising: an ankle componenthaving a hole in a front part of the ankle component, wherein the frontpart of the ankle component is about 5° to about 25° higher than a rearpart of the ankle component with respect to a horizontal axis parallelto a level ground surface; a forefoot component; a heel component; andan elliptical hinge comprising a circular part on the forefoot componenthaving a rounded top surface and two flat side surfaces, said circularpart being connected to a rear part of the forefoot component and beingfit into the hole of the ankle component, so that the circular partpronates and supinates, wherein the ankle component, forefoot component,and heel component are three separate components, said forefootcomponent being directly connected to the front part of the anklecomponent and said heel component being directly connected to a rearpart of the ankle component.
 19. A modular prosthetic foot according toclaim 1, wherein the structure of the modular foot simulates ananatomical subtalar joint.
 20. A modular prosthetic foot according toclaim 1, wherein the forefoot component has a J-shape, C-shape, orS-shape.